Sprayable Off-On DCP detection: Biocompatible carboxamide-based sensor with fluorescent signaling and colorimetric coagulation trigger

Detecting hazardous nerve agents is essential due to their extreme toxicity and potential for severe harm, necessitating rapid and reliable sensing solutions. This study introduces a compact, high-performance sensor designed for diethyl chlorophosphate (DCP) detection, a commonly used nerve agent simulant, engineered for rapid response and easy field readiness. Leveraging triphenyl phosphite as an innovative synthetic modification instead of the traditional triphenyl phosphate, the sensor achieved a higher yield, an acceptable limit of detection (LOD, 4.75 µM), and enhanced sensitivity. Characterization techniques (including Density Functional Theory (DFT) analysis, HOMO-LUMO gap, and electrostatic potential mapping) align with XPS, NMR, and Raman spectroscopy results, confirming the sensor's structural integrity and operational efficacy. The sensor's rapid response is showcased through distinct chromogenic and fluorescence shifts, enabling naked-eye visual identification. The selectivity study reveals strong specificity for DCP, with no response to even HCl, H₃PO₄, NaOH, or structurally similar compounds, ensuring reliability in complex environments. Biocompatibility tests on HaCaT and CD-1064sk cell lines further support their safe use by operators. With safe near-UV-A excitation (385 nm) and an extended linear range (1–50 Equiv) at high DCP concentrations, this sensor is a valuable tool for emergency applications where immediate detection and response are crucial.